144 HALF HOURS WITH USTSECTS. [Packard. 



Epliydi-a, with its rather short, thick tubes and fleshy feet, 

 clambers over green sea weeds in salt pools removed above 

 the reach of ordinary tides, or lives in the brine pools of 

 Illinois, or the salt lakes of the West, The aquatic larva 

 of one of the Tipulids or crane flies (Ptychoptera) has a 

 long respiratory tube, while in the pupa there is one attached 

 to the head and much longer proportionally than in the lar- 

 val Helophilus. 



Among those larval flies which are obliged to ascend to 

 the surface to breathe, is the young Mosquito (Fig. 109 ; a, 



Fig. 108. 



Helophilus larvae (after Figiiier). 



larva; b, pupa; a, paddles at end of body of pupa). Its 

 body is beautifully adapted for going through its aquatic 

 evolutions. The head and thorax are so large and bulky 

 that it cannot ascend and lie motionless in a horizontal 

 position, as in the young Anopheles, which lies before us in 

 a dish as we are writing ; but it hangs head downwards and 

 breathes by means of a spiracle lodged in one of the large 

 tubes into which the end of the body subdivides, the posi- 



16 



